As you can see, the POM's last modified date is recent, but nevertheless the content is old. In fact it still matches the pom.sha1, which was last updated in December! How is this possible?
This is a very insidious bug, and you would help a lot of people by fixing it ASAP.

Peter Niederwieser
added a comment - 05/Mar/10 12:06 PM - edited I have exactly the same issue with 2.2.1. After changing and deploying parent POM, I run build with -U (on a different machine). Excerpt from output:
[INFO] snapshot org.spockframework:spock-parent:0.4-groovy-1.7-SNAPSHOT: checking for updates from central
[17:48:33]: Downloading: http://xxx/artifactory/repo/org/spockframework/spock-parent/0.4-groovy-1.7-SNAPSHOT/spock-parent-0.4-groovy-1.7-SNAPSHOT.pom
[17:48:33]: Downloading: http://xxx/artifactory/repo/org/spockframework/spock-maven/0.4-groovy-1.7-SNAPSHOT/spock-maven-0.4-groovy-1.7-SNAPSHOT.jar
Maven says that it is downloading spock-parent POM, but it doesn't end up in the local repo. Compare to the output after manually deleting the old POM from the local repo:
[INFO] snapshot org.spockframework:spock-parent:0.4-groovy-1.7-SNAPSHOT: checking for updates from central
Downloading: http://xxx/artifactory/repo/org/spockframework/spock-parent/0.4-groovy-1.7-SNAPSHOT/spock-parent-0.4-groovy-1.7-SNAPSHOT.pom
8K downloaded (spock-parent-0.4-groovy-1.7-SNAPSHOT.pom)
Here we get "8K downloaded", which we didn't get before. The local repo now contains the correct POM, and the build succeeds.
Here is what the local repo looked like before I manually deleted the old POM:
drwxr-xr-x 6 pniederw admin 204 Mar 5 16:48 .
drwxr-xr-x 3 pniederw admin 102 Dec 14 13:47 ..
-rw-r--r-- 1 pniederw admin 331 Mar 5 16:48 maven-metadata-central.xml
-rw-r--r-- 1 pniederw admin 40 Mar 5 16:48 maven-metadata-central.xml.sha1
-rw-r--r-- 1 pniederw admin 9048 Mar 5 16:48 spock-parent-0.4-groovy-1.7-SNAPSHOT.pom
-rw-r--r-- 1 pniederw admin 40 Dec 14 13:47 spock-parent-0.4-groovy-1.7-SNAPSHOT.pom.sha1
As you can see, the POM's last modified date is recent, but nevertheless the content is old. In fact it still matches the pom.sha1, which was last updated in December! How is this possible?
This is a very insidious bug, and you would help a lot of people by fixing it ASAP.